Hard disk drives are very important data saving carriers for the present computer, capacity of the hard disk drive has been increased gradually because of the technical development, and comparing with compact disk (CD) the hard disk drive has the advantages of large capacity and high speed data transmission. Therefore, a mobile hard disk drive (external hard drive enclosure) has become the common device in the present.
3.5 inches hard disk drive has largest capacity and long-life characteristic. As a result, many users like to use it. However, the 3.5 inches hard disk drive has large size and higher power consumption. For the 3.5 inches hard disk drive, besides of 5 V from an USB port, a 12 V input voltage to drive a motor is also needed. Therefore, the 3.5 inches mobile hard disk drive (or 3.5 inches hard drive enclosure) needs an extra 12 V power adapter to drive the motor, and this causes inconvenience in carrying.
In order to solve the above-mentioned problem, a solution is disclosed in the patent publication US20140091621. In US20140091621, a battery is disposed in a shell and used to provide the energy to start up the hard disk drive. In the 3.5 inches mobile hard disk drive disclosed in US2014091621, any extra power supply is not needed, but a high-cost battery having lower inner resistance and occupying large space is needed. Furthermore, when the motor is driven by the USB port in a high output current, the output voltage of the USB port may be decreased and not high enough to drive the control circuit in the mobile hard disk drive.
It is thus desirable to provide a cheapersmaller battery design to drive 3.5 inches hard disk drive with only 5 V from USB port and does not need any extra 12 V power adapter.